1. Field of the Invention
This invention relates to an oil recirculation system for returning the bearing lubricating oil purged through the bearing during rotation to an oil reservoir to maintain the bearing surfaces lubricated, and more particularly, to such a system wherein the oil is returned through a stationary passage housing a readily removable oil filter assembly therein.
2. Description of the Prior Art
It is well known in a bearing lubrication system to provide a reservoir of oil adjacent the bearing to cause the oil to become deposited on the bearing and lubricate it. However, the centrifugal force at the rolling bearing surfaces causes the lubricating oil to be expelled from the supply reservoir. Tapered roller bearings have a special lubricating problem due to their conical shape. Such bearings produce a pumping action from the apex side outward toward the open end of the cone. One manner of maintaining the bearing surface wetted by the oil is to provide a seal on the side of the bearing opposite the reservoir and, once the volume defined by the seal and the bearing receives a certain amount of the oil, the bearing will no longer provide sufficient pumping action from the reservoir and will have oil on both sides at sufficient depth to maintain the bearing lubricated. This requires an excess oil fill to the reservoir causing a heat build-up because of excessive oil churning. Such a sealed volume for trapping the oil is shown in U.S. Pat. No. 3,941,012, of common assignee to the present invention, and directed to an in-line motor internal combustion engine-compressor drive mechanism. The tapered roller bearings of this apparatus tend to purge the lubricant from the inner rotor cavity in the above-described manner.
An alternative well known method of maintaining the bearing surface wetted with lubricant is to recirculate the oil purged by the pumping action of the tapered roller bearing back into the oil reservoir, through suitable passages. This has the advantage of requiring less lubricant, but the assembly generally requires a greater number of parts with close tolerance machining to provide the oil passages. U.S. Pat. No. 561,028 shows an early application of such a bearing oil recirculating arrangement.